The Moments of a Springboard

The diagram (not included) shows a straight, horizontal swimming bath spring board of length 4m and weight 300N. It is freely hinged at A and rests on a roller at B where AB=1.6m. A boy of weight 400N standard at end C.
a) show directions of forces acting on A and B
b) calculate magnitudes of forces at A and at B

2. Relevant equations

A______________B______________C
AB= 1.6m
BC= 2.4m
AC= 4m

3. The attempt at a solution
Weight of board put at centre point (0.4m from B and 2m from C)
RA assigned as reaction force at A
RB assigned as reaction force at B